Refrigeration apparatus



jam, M, we L.. s. CHADWICK REQERIGERATION APPARATUS Filed March 10, 1953 5 Sheets-Sheet l E.; g s. cHADwncK REFRIGERATION APPARATUS Filed March 10, 1935 3 Sheets-Sheet 2 Jan.. 14, 1936., L. s. cHADwlcK REFRIGERATION APPARATUS Filed March 10, 1955 3 Sheecs--SheeI 3 Patented Jana. 144 1936 2,027,631 REFRIGERATION APPARATUS Lee s. Chadwick, shaker Heights, ohio, assignmto Perfection Stove Company, Cleveland, hio,

a corporation of Ohio Application March ic, 1933, serial No. 660,275

25 Claims.

'I'his invention relates, generally, to refrigeration apparatus of the intermittent absorption class, and more particularly to improvements in means for returning residue liquid from the evaporator section of the apparatus to the generator absorber section at the beginning of a cycle of operation, which beginning is characterized by what is known as the heating-condensing period.

Means for performing this transfer of residue ,liquid is described and claimed in Letters Patent No. 1,816,975, dated August 4, 1931, the present invention being directed particularly to improve.- ments in the type of liquid return disclosed in said patent. Briey, the apparatus in connection with which the liquid return is employed comprises a closed system involving a generator-absorber section, an

preferably, in suflicient quantity to practically flll the generator-absorber when all of the mixture is present therein. f

When heat is applied to the generator-absorber, the mixture contained therein boils and the vapors, after being dehydrated as completely as possible, are condensed and the resultant liquid is delivered to the evaporator section of the apparatus. Upon the cessation of heat, the prac- Y tically pure anhydrous refrigerant in the evaporator gradually gasifles and returns to the generator-absorber section where it is reabsorbed. Any liquid left in the evaporator section at the conclusion of the evaporating period, and which consists principally of absorbent condensate resulting from vapors that got pest the dehydrator during the heating-condensing period, is known as the residue liquid. v

At this point it may be explained that, `as shown in the aforesaid Letters Patent, the evaporator section of the apparatus is above the plane of the generator-absorber section and the liquid return tube or conduit extends from a sump or low point in the evaporator section upwardly and thence laterally and downwardly into the generator-absorber section, the same being in the nature of a Siphon. It is through this tube or conduit that the residue liquid is transferred from' 4 the evaporator section to the generator-absorber section, and the principle upon which it operates (CL (i2-120.5)

may be explained as follows: At the beginning of the heating-condensing period the pressure throughout the system rises rapidly and, as a consequence thereof, the liquid in the generatorabsorber section, and the residue liquid in the evaporator section, are forced up the respective branches of the liquid return tube or conduit, trapping between the two rising columns of liquid the gas that occupied the tube or conduit under the original internal low pressure condi- 1@ tion of the apparatus, and which gas is particularly rich in refrigerant,.and, by reason of the same being wholly or partially absorbed by the rising liquid, the two columns thereof are caused to approach each other and eiect a suiciently 15 continuous body of liquid throughout'the length of the liquid return tube or conduit to cause a siphonic action to be set up which draws over into the generator-absorber section of the appaf ratus, practically all of the residue liquid that was 2o present in the evaporator section In the apparatus disclosed in the aforesaid patent, a part of the liquid return tube or conduit is in intimate heat exchanging relation to the hot vapors as they rise through thel vapor delivery conduit during the heating-condensing period, and this is for the purpose of elevating the temperature of such part of the liquid return tube so as to cause any refrigerant liquid which might tend to pass therethrough during the condensing 3o period toflash into gas and interrupt the siphonic action so as to avoid robbing the evaporator of any of its charge of anhydrous refrigerant. In some cases this arrangement was found to be too effective and actually prevented the return oi' all 35 of the residue liquid. It was observedv that, at times, the siphonic action would be stopped by the flashing into gas of a relatively small amount of refrigerant liquid that would return, early in the operation, with some oi the absorbent liquid 40 and, as a consequence, an appreciable amount of residue liquid would be left in the evaporator. In z and the heating up of the ,liquid return tube or conduit to allow a complete return of the accumuv lated residue liquid. 'v

It is the fundamental purpose of the present invention to provide means that wili insure a sufficient time lag between the beginning oi' the 50 heating-condensing period, when` the liquid re- Y turn tube is relatively cool,'an the stage in the progress of such period when said tube is heated, to insure a substantially complete return of the :residue liquid;l and which means thereafter will uid return tube obviously preventing any siphonlc maintain the temperature of the liquid return tube high enough to obviate any possibility of the return of pure anhydrous refrigerant during the remainder of the heating-condensing period.

Again, and more broadly, the invention may be said to have as its main purpose the provision of means for effecting the return of residue liquid from the evaporator section of the apparatus to the generator-absorber section thereof for a relatively definite time during the early stage of a cycle of operation and which will function thereafter to positively prevent the return of anhydrous refrigerant.

As to the present preferred form of the invention, its object may be recited as that of provid# return tube and some part of the system whose temperature is materially elevated during the heating-condensing period, and wherein the mass of this heat conducting means or bar is utilized to effect'a suflcient delay in the transmission o'f heat to the liquid return tube to allow ample time for the return of the residue liquid before the tubebecomes hot. Furthermore, when the mass of the aforesaid heat conducting means or bar once be comes hot, it is not readily cooled by any small slugs of anhydrous refrigerant that might, for any reason, pass through the liquid return tube. Consequently, after said heat conducting means or bar once reaches'a high temperature, it is extremely effectivein preventing the return of anhydrous refrigerant and thus guards against robbing the evaporator of its full charge of refrigerant for the subsequent cooling period.

The invention is susceptible to several modiflcations. For example, in place of the heat conducting means or heat bar above referred to, means may be associated with the liquid return tube for sustaining in contact therewith a body of cool liquid which is later displaced by a' body of heated liquid, thereby to effect the same result as that above described of maintaining the liquid return tube cool for a certain period yof time and thereafter causing it to be heated.

As a further modification, means may be pro vided for applying hot vapors to the outside oi' the liquid return tube to heat it up at the proper time.

A further means, which may be used alone or in combination with those above described, `for attaining the purpose of the invention, is a vent for the Siphon-like liquid return conduit, which vent may be in the nature of a tube that leads from a high part of said conduit to a point in the gas return conduit of. the system below the minimum liquid level in the generator-absorber and so arranged that its lower end is closed by liquid from the generator-absorber during the heatingcondensing period and is open when said liquid is displaced by the returning gas during the evaporating-absorbing period, the venting of the liq action after the heating-condensing period has ceased.

The several embodiments of the invention above referred to are illustrated in the accompanying drawings wherein Fig. 1 is a diagrammatic representation of an intermittent absorption refrigerating machine or apparatus embodying the heat bar for effecting delayed transmission of heat4 from the vapor delivery conduit to the liquid return tube, this embodiment alsoincludinst the vent for said tube; Fig. 2 is a sectional detail, on a somewhat larger scale than that of the preceding view, through the heat bar and the liquid' return tube 4and vapor delivery conduit to which it is attached, the plane of section being indicated by the line 2--2 of Fig.' 1;v Fig. 3, which is on the same scale as Fig. 2, is a sectional detail of the junction between the liquid return tube or conduit and the vent tube; Fig. 4 is a view, similar to Fig. 1-, showing the form of the invention in which means is provided for sustaining a body of hot liquid incontact with the high part of the liquid return tube or conduit during the latter part of the heating-condensing period; Fig. 5 is a fragmentary View. of the refrigeration apparatus or machine showing a further modication which. in all other respects than those revealed, is identical'with that illustrated in Fig. 4; and Fig. 6

is a diagrammatic representation of an intermittent absorption refrigerating machine or ap- The vessel which constitutes the generatorabsorber is designated I and a vapor delivery conduit 2 leads therefrom to the bottom of a receiver vessel 3 which communicates, through a tubular. column ,4, withthe evaporator 5. The vessel I will be referred to in some instances as the generator-absorber section of the apparatus, while the parts 3, 4 and 5'will be referred to as the evaporator section. A' part 2a of the vapor delivery conduit constitutes a dehydrator, and,F a coiledq portion 2b thereof forms "the condensing un'it, beyond which the' conduit is shown as reduced in diameter and as terminating adjacent the bottorn of the vessel 3. A gas return conduit 6 leads from the evaporator section of the apparatus or, more specifically, from the top of the vessel 3, to the generator-absorber section, the same entering the lowerF portion of the vessel I and terminating therein below the minimum liquid/level indicated by the line a. The maximum liquid level in said vessel is shown by the line b.

Means for delivering heat to the generator-absorber section is indicated at '1, and may consist of a suitable hydrocarbon burner supported in operative relation to the vessel I.

It will be readily understood by those familiar with the class of machines to which this invention pertains that the condensing unit or coil 2b, desirably together with the dehydrator 2, is enclosed in a tank of cooling liquid, and that the evaporator 5 is placed inside the refrigeration compartment of a suitable cabinet, the receiver 3 preferably being insulated from such compartment. A showing of these features was omitted for the sake of clearness as their inclusion would have necessitated a less diagrammatic representation of the more important parts of the appal ratus.

descends to the generator-absorber section, which .P

is at a considerably lower elevation than the evaporator section, entering the Vessel I and terminating therein at a point well below the maximum liquid level. In fact, it is shown in the present instance as having its end disposed below of the' liquid return tube being of relatively small diameter, cause the liquid to rise therein at a reasonably rapid rate during the beginning of the heating period when the pressure is` rising rapidly in the system, and as a consequence, the siphonic action is initiated early in this phase of the cycle of operation'and by having the middle portion of the tube of greater diameter avoids subsequent carrying over of liquid by bubbles of gas entering the receiving end of the tube, as such bubbles will break into the portion o f the tube of larger diameter and allow the liquid toiiow back into the evaporator.

In the form of the invention illustrated in Figs. 1 to 3, a so-called heat bar in the form of a relatively massive body of metal, and designated lll, joins adjacent portions of the vapor delivery conduit 2 and the liquid return tube or conduit 8,

the bar or mass of metal being in intimate heat l exchanging relation to the conduits. as by being welded thereto. 'This arrangement is best illustrated in Fig. 2.

At the conclusion of a cycle of operation the heat bar i@ is cool; the mixture of refrigerant and absorbent liquids stands in the generatorabsorber to about the level indicated by the dotted line b, and the residue liquid may stand in the evaporator` end of the system to the level indicated by the dottedline c.

To start a cycle of operation. heat is applied to the generator-absorber as by lighting the burner ll. As a result thereof, the mixture within the vessel tl boils and the vapors ascend through the conduit 2 and are dehydrated, at least to a very high degree, while passing through the dehydrator 2B. The refrigerant vapors pass on through the condensing unit or coil 2 and are condensed therein and gravitate to the evaporator section-more accurately, to the receiver 3. In

the meantime, the pressure within the system has risenrapidly and has forced some of the residue liquid in the evaporator section and some of the mixture in the generator-absorber section upwardly into the respective ends of the liquid return tube or conduit, andthe gas that is trapped within said tube or conduit between the rising'A columns of liquid becomes more or less absorbed by the 'liquid' drawing the two columns toward each other" until .a suiiicently continuous body of liquid is established within the returntube or conduit to set up a siphonic action that will carry all, or practically all, of the residue liquid from the evaporator section 'over into the .generatorabsorber section. v

During this time, the heat given off by the l vapors rising through the delivery conduit :2 has gradually elevated the temperature of the heat bar l0 until by the time the residue liquid is re turned, said bar'has transmitted the heat to the liquid return tube or conduit, so that in case any of thaanhydrous refrigerant tends to siphon over.

into the generatorabsorber,` it will. upon reaching the zone of hat given oii by the bar it flash into gas and interrupt any s iphonic iiow that may havel been started. Thus, during the remainder of the heating period there is vno liability of withdrawing the pure anhydrous refrigerant liquid from the evaporatorsection ofthe apparatus that is being delivered-thereto from the condenser. p In 'or der to.obtain the maximum in the transfer of heat fromthe hotvapors in the conduit 2 to liquid turn conduit, the same being shown as a tube ii whose upper end opens into the larger portion of the conduit 8 adjacent the high part of said conduit, as illustrated in detail in Fig. 3, said tube extending downwardly to where it joins the gas return conduit Sbelow the plane of the minimum liquid level in the generator-absorber section of the apparatus, the tube i l being increased in diameter approximately to that of the conduit t downwardly from a point substantially midway between its ends.

At the conclusion of a cycle of operation, the liquid stands in the lower ends of the gas return conduit t and tube i i to a level corresponding to the maximum liquid .level in the generatorabsorber section of the apparatus, indicated by the dotted line b. During the heating-condensing period when the pressure within the system is high, the liquid is forced up into the lower potion of the conduit t and into the larger end of the tube ii. At the conclusion of such period, however, and during the cooling-evaporating period which follows, the liquid that was in the lower portions of the gas return conduit t and tube Ui is displaced by the refrigerant gas as it returns through said conduit to the, generatorabsorberI for re-absorption by the relatively weak liquor therein, thereby unsealing the vent tube. Thus it will be seen that, from the very beginning of the cooling-evaporating period, the liquid return tube or conduit is vented which will posi'- tively prevent its functioning as a siphon to rob the evaporator of itsfull charge of anhydrous refrigerant.

In the form of the invention illustrated in Fig.

4, a closed receptacle i5 encloses the high part of the liquid'return tube or. conduit t, .and the same communicates through a tube i6 with a vessel it that surrounds a part of the vapor delivery conduit 2. It will be observed that the tube i6 opens into the vessel i8 adjacent the bottom of the'latter, and,`as indicated, said vessel is 'waten generated within said vessel to force the hot liquid up through the tube it and into the receptacle l5 where it will warm the adjacent portion of the liquid return tube or conduit 8 thereby to prevent siphoning of anhydrous refrigerant liquid by causing it .to flash into gas.v Sumcient time is afforded, however, before this heating up of the vliquid return conduit takes pace to permit the return of the residue liquid from the evaporator sectinof the apparatus to the generator-absorber section thereof.

A slight modication of the form ofthe invention just described is illustrated in Fig. 5, where a revised part of the diagram of Fig. 4 is shown.

practically lled with a liquid, which may be In other respects, the system may be as illustrated in the previous view. I n Fig. 5 a vessel I8n is substituted for the vessel I8 of Fig. 4, and it is placed inside the generator-absorber I; and the tube I6, which is the equivalent of tube I6 of the former modification, extends down through the top portion of the generator-absorber I and joins the top of the vessel Ia. The vessel I8 contains a body of liquid, and as it is caused to boil by the surrounding heat in the vessel I, its vapors will ascend through the tube ||ia and fill the receptacle I5, causing the heating up of the adjacent part of the liquid return tube or conduit 8. It will be understood, of course, that the boiling of the contents of the vessel I8l is sufficiently delayed to permit normal functioning of the liquid return tube or conduit 8 so as to insure return of the residue liquid from the evaporator section of the apparatus to the generator-absorber section. It will be noted that the receptacle I5 and tube I6 or I E are arranged to drain toward the vessel 4I8 or I8ab so that all liquid or condensate will gravitate to the latter. Here it may also be explained that in Fig. 4, the tube I6 may terminate at the top of the vessel I8, in which case only the vapors of the liquid within said vessel would be communicated to the receptacle I5; and reversely, the tube |63 in Fig. 5 may be continued to the bottom of the vessel I8 so that in this case the heated liquid would be transferred by the action of the vapor in said vessel to the receptacle I5. These alternative forms are so obvious that specic illustration is deemed unnecessary.

- In the modification illustrated in Fig. 6, con-l densate drains from the dehydrator 2"L through a. tube 20 to a vessel 2| toa heightat whichit overflows through a tube 22into a sleeve-like receptacle 23 that surrounds a portion of the liquid return conduit 8 adjacent the high part of the latter. The receptacle 23 drains, through a tube 24 into the generator-absorber section of the apparatus, said tube being shown as entering the vapor delivery conduit a short distance above the vessel I. To prevent the siphoning of liquid from the vessel 2| through the overflow tube 22, said tube is vented through a pipe 25 to the tube 20.

Prior to the initiation of a cycle of operation,

the parts of the apparatus are cool, as is also the liquid in the vessel 2|. Upon the starting of a cycle of operation by applying heat to the generator-absorber, as by lighting the burner 1, the liquid in the vessel I starts to boil and the hot vapors rise through the relatively large vapor delivery conduit 2 and as they pass through the dehydrator 2, the absorbent vapors condense and the resultant warm liquid gravitates through the tube 20 to the vessel 2| causingsaid vessel to overflow through the tube 22 into the receptacle 23, and since said tube -22 communicates with the bottom of the vessel 2|, the cool liquid will rst be transmitted to the receptaclel 23. The ow of relatively cool liquidcontinues long enough to insure a siphoning of the residue liquid from the evaporator section of the apparatus to the generator-absorber section, after which warm liquid overows from the vessel 2| into the receptacle 23 and, heating the liquid return tube or subsequent relatively prolonged cooling-evaporating period of the cycle of operation.

Having thus described my invention, what I claim is:

1. The combination with refrigeration apparatus of the intermittent absorption type wherein a refrigerant fluid and an absorbent fluid are used, and comprising a closed system involving a generator-absorber section, an evaporator section, and communicative means for conveying refrigerant fluid between the sections in the attainment of a complete operative refrigeration cycle, together with condensing means and means for intermittently supplying heat to the generatorabsorber section, the portion of each cycle during which the heat supplying means is effective being known as the heating period, and a conduit for returning liquid from the evaporator section vto the generator-absorber section at the beginning of a heating period; of means that becomes eiective a predetermined and relatively prolonged interval of time after the beginning of the heating period for maintaining a part of said conduit hot during the remainder of said period, thereby to vaporize liquid refrigerant entering said part of the conduit and consequently interrupt the flow of liquid through the conduit so as to prevent the return of liquid thereafter.

2. The combination with refrigeration apparatus of the intermittent absorption type wherein 'a 'refrigerant fluid and an absorbent fluid are used, and comprising a rclosed system involving a generator-absorber section, an evaporator section, and communicative means for conveying refrigerant fluid between the sections inthe attainment of a complete operative refrigeration' entering said part of the conduit so as to interv rupt the flow of liquid through the conduit and prevent the return of liquid thereafter.

3. The combination with refrigeration apparatus of the intermittent absorption type wherein a refrigerant fluid and an absorbent fluid are used, and comprising a closed system involving a generator-absorber section, an evaporator section, and communicative means for conveying refrigerant fluid between the sections in the attaininent of a complete operative refrigeration cycle, together with condensing means and means for intermittently supplying heat to the'generator-absorber section, the portion of yeach cycle during which the heat supplying means is effective being known as the heating period, and a conduit for returning liquid from the evaporator section to the generator-absorber section 4at the beginning of a heating period; of means rendered effective an appreciable interval of time after the beginning of the heating period by heat from a part of the system whose temperature is elevated to a relatively high degree during the heating period for imparting heat to a part of the aforesaid conduit thereby to vaporize liquid refrigerant entering said part so as to interrupt the fioul of 'liquid through the conduit and prevent the return of liquid thereafter.

4. The combination with refrigeration ap-.

paratus of the intermittent absorption type wherein a refrigerant fluid andv an absorbent fluid are used, and comprising a closed system involving a generator-absorber section, an evaporator section, and communicative means for conveying refrigfrant fluid between the sections in the attainment of a complete operative refrigeration cycle, togethervvith condensing means and means for intermittently supplying heat to the generator-absorber section,vthe portion of each cycle during which the heat supplying means is effective being known as the heating period, and a conduit for returning liquid from the evaporator section to the generator-absorber section at the beginning ,of a heating period; of vent means leading from a part of said conduit and liquid sealed by liquid from the generatorabsorber section of the system during the lheat-- ing period and cleared of liquid by gas returning from the evaporatorsection of the system to the generator-absorber' section during the evaporating-absorbing period thereby to vent said conduit and prevent the return of liquid during the latter period.

5. In refrigeration apparatus of the class set forth including evaporator and generator-absorber sections and incorporating a conduit for returning residue liquid 'from the evaporator section to the generator-absorber section at the beginning of a heating period, means for maintaining a part of said conduit at a relatively lowtime after the beginning of each heating periodv and for then heating said part to a relatively high temperature and maintaining it so during the remainder of the heating period.

7. In refrigeration apparatus of the class set forth including evaporatory and generator-absorber sections and a conduit for returning residue liquid from the evaporator section to vthe y generator-absorber section at the beginning of a heating period, a heat absorbing body having considerable mass arranged inthermal contact with a part of said conduit, said body remaining at a relatively low temperature for a predeterwith a part on said conduit, said body being also in thermal 'contact with a part of the apparatus whose temperature is elevated to a. relatively high degree during the heating period, the

remaining at a relatively low' temperature for a "predetermined prolonged interval of time during the early part of each heating period and thereafter being heated and maintained at a relatively high temperature during the remainder of the heating period by reason of its thermal Contact with the previously mentioned part of the apparatus.'

9. In refrigeration apparatus of the class set forth `including evaporator and generator-absorber sections and a conduit vfor returning resi` due liquid from the evaporator section to the generator-absorber section at the beginning of a. heating period, means associated with said conduit for maintaining it relatively cool for a predetermined intervalvof time at the beginning oi each heating period and for thereafter maintaining it at a relatively high. temperature during the remainder of said period.

l0. In refrigeration apparatus ofthe class described, in combination with a vapor. delivery conduit and a valveless liquid return siphon, a

heat conductingy body of relatively large mass in thermal contact with the conduit and siphon. l

1l. In refrigeration apparatus of the class described, in combination with a vapor delivery conduit and a valveless liquid return Siphon, a

-heat conducting element of. relatively large mass connecting the conduit and Siphon.

l2. In refrigeration apparatus o f the class described, in combination-With a vapor delivery conduit and a valveless liquid return Siphon, the latter being arranged above the former, a heat conducting element of relatively large mass connecting the top side of the vapor delivery conduit with the underside ,ofI the liquid return Siphon.-

13. In refrigeration apparatus of the class described, in combination with a vapor delivery conduit and a valveless liquid return Siphon, a relatively heavy heat bar connecting adjacent parts "of the conduit and Siphon.

1li. In refrigeration apparatus of the class set forth, in combination with the vapor delivery conduit and the liquid return conduit, a receptacle in intimate heat exchanging relation to a part of the liquid return conduit, a vessel at a lower elevation than said receptacle in similar relation to the vapor delivery conduit and containing a fluid, and means communicatively connecting said receptacle and vessel.

part of the liquid return conduit, a vessel sur- "f rounding the vapor delivery conduit and containing a body of liquid, and a tube communicatively connecting the receptacle and vessel and `being so arranged as to permit the former to drain therethrough to the latter, said tube opening into the vessel adjacent the bottom thereof.

16. In refrigeration apparatus of the class set forth including evaporator and generator-absorber sections and a liquid return conduit through which residue liquid is returned from the evaporator section to the generator-absorber section of the apparatus, a receptacle in intimate heat exchanging relation to a part of said conduit and arranged to draininto the generatorabsorber section, a vessel communicating with a part of the apparatus and so arranged as toreceive hot condensate during the heating-condensing period of a cycle oioperation, and communicative connections through which-said vessel overdows into'thaaforesaid receptacle.

17. In refrigeration apparatus of the class set forth including evaporator and generator-absorber sections and a liquid return conduit through which residue liquid is returned from the evaporator section to the generator-absorber section of the apparatus, a receptacle in intimate heat exchanging relation to a part of said conduit and arranged to drain into the generatorabsorber section, a vessel communicating with a part of the apparatus and so arranged as to receive hot condensate during the heating condensing period of a cycle of operation, communicative connections through which said vessel overows into the aforesaid receptacle, and vent means communicating at its ends with parts of the refrigeration system on opposite sides of said vessel and bypassing the same.

18. In refrigeration apparatus of the class set forth, in combination with a liquid return conduit and a gas return conduit, a vent leading from an elevated part of the liquid return conduit and communicating with the gas return conduit at a point below the plane of the minimum liquid level in the generator-absorber section of the apparatus.

19. In refrigeration apparatus of the class set forth, in combina' ion with a liquid return conduit and a gas return conduit, the former conduit being enlarged in diameter intermediatel its end portions, a tube through which an elevated part of 'theenlarged portion of the liquid return conduit communicates with a part of the gas return conduit below the plane of the minimum liquid level in the generator-absorber section of the apparatus, said tube being enlarged in diameter from its junction with the gas return conduit for a material distance .hereabove.

20. In refrigeration apparatus of the class set forth, including evaporator and generator-absorber sections and a siphon-like conduit for returning residue liquid from the evaporator section to the generator-absorber section of the apparatus, a tube through which the elevated portion of said siphon-lkc conduit is vented to the generator-absorber section and so arranged as to be sealed by liquid therefrom excepting during the evaporating-ahsorbing period of a cycle of operation.

21. In refrigeration apparatus of the class set forth, including evaporator and generator-absorber sections and a Siphon-like conduit for returning residue liquid from the evaporator secliquid from the generator-absorber section excepting when suchliquid is displaced by the returning gas.

22. In refrigeration apparatus of the class set forth including evaporator and generator-absorber sections and a. conduit in constant open communication with both of said sections for returning residue liquid from the evaporator section to the generator-absorber section at the beginning of a heating period, means operating with a. substantially definite time lag for effecting by conduction a materially delayed transmission of heat to said conduit from a part of the apparatus whose temperature is relatively high during the heating period.

23. In refrigeration apparatus of the class set forth including evaporator and generator-absorber sections and a conduit in constant open communication with both of said sections for returning residue liquid from theevaporator section to the generator-absorber section at the beginning of a heating period, means operating with a substantially definite time lag and influenced by the elevated temperature of the part of the apparatus that becomes heated during said period for transmit. ing heat by conduction to the aforesaid conduit a predetermined and relatively prolonged interval of time after the beginning of said heating period. l

24. In refrigeration apparatus of the class described including an evaporator section and a generator-absorber section, and a Siphon in constant open communication with both of said sections for returning residue liquid from the evaporator section to the generator-absorber section at the beginning of a heating period; means operating with a definite time lag that is rendered effective a materialy interval of time after the beginning of the heating period, by the elevated temperature of a part of the system heated to a. relatively high degree during the heating period and to which said means is subjected, for imparting heat by conduction to a part of the siphon that is above the plane of its higher end.

25\. In refrigeration apparatus of the class set forth, including an evaporator section and a. generator-absorber section, and a. liquid return conduit through which residue liquid. is returned from `the evaporator section to the generatorabsorber section; a receptacle in intimate heat *exchanging relation to a part of said conduit, a. vessel arranged to be heated by the heat of the vapors generated in the generator-absorber section, said vessel containing a fluid, and means through which said receptacle and vessel cmmunicate.

LEE S. CHADWICK. 

